<p>Letter to the Editor Wall Street Journal By S. Fred Singer, SEPP, Oct 3, 2014</p><p>Contrary to the Santer-Stocker letter (WSJ Oct 2), the climate models used by the UN-IPCC in its five Assessment Reports (AR) since 1990 have failed miserably in their persistent attempts to demonstrate evidence for AGW (anthropogenic global warming). As pointed out in reports of the NIPCC (Non-governmental International Panel on Climate Change www.NIPCCreport.org), the IPCC 'evidence' cited has changed from AR to AR -- without any explanation:</p><p>AR-1 relied on an imperfect correlation; for AR-2 Mr. Santer 'manufactured' a 'Hotspot,' an upper-atmospheric warming trend in the tropics, which doesn't even exist; AR-3 relied on Michael Mann's 'Hockeystick' graph, since discredited. Both AR-4 and AR-5 (which Mr. Stocker co-chaired) used ‘evidence’ based on a circular argument that defies elementary logic. They try to ignore the fact that current IPCC models cannot account for the absence of a warming trend during the past 15 or more years.</p><p>Admittedly, IPCC faces a difficult task: To establish the reality of AGW, they must show inadequacy of the 'null hypothesis' of natural climate variability – which is backed by geological data reaching back to pre-human ages.</p><p>The writer, an atmospheric physicist and 'expert reviewer' of IPCC reports, founded the NIPCC in 2007 to correct major deficiencies of the IPCC.</p>